Pressure supply system having means for controlling an output pressure thereof

A pressure supply system for on-board equipment of a vehicle, comprising:

• a pump actuated by power drive means;
• an output conduit connected to an output end of said pump;
• an accumulator connected to said conduit;
• a pressure sensor for detecting an inner pressure of said accumulator;
• a speed sensor for detecting a travelling speed of said vehicle;
• and
• a control unit for controlling operation of said pump according to an output of said pressure sensor so as to maintain the inner pressure of said accumulator as detected by said pressure sensor within a prescribed range, said control unit including memory means for defining an upper limit pressure value and a lower limit pressure value,
• said control unit activating said pump when the inner pressure detected by said pressure sensor has reached the lower limit pressure value and deactivating said pump when the inner pressure detected by said pressure sensor has reached the upper limit pressure value,
• at least one of the upper and lower limit pressure values being made higher as the vehicle speed detected by said speed sensor is increased.

A pressure supply system for on-board equipment of a vehicle comprising;

• a pump actuated by power drive means;
• an output conduit connected to an output end of said pump;
• an accumulator connected to said conduit;
• a pressure sensor for detecting an inner pressure of said accumulator;
• a speed sensor for detecting a travelling speed of said vehicle;
• and
• a control unit for controlling operation of said pump according to an output of said pressure sensor so as to maintain the inner pressure of said accumulator as detected by said pressure sensor above a predetermined minimum pressure, said control unit including memory means for defining a reference pressure value for the minimum pressure,
• said control unit activating said pump when the inner pressure detected by said pressure sensor has dropped below the reference pressure value, and deactivating said pump after elapsing of a predetermined time period following such an activation of said pump.

A method for controlling a pressure supply system for on-board equipment of a vehicle wherein the pressure supply system incorporates a pump actuated by power drive means, an output conduit connected to an output end of the pump, an accumulator connected to the conduit, a pressure sensor for detecting an inner pressure of the accumulator, a speed sensor for detecting a travelling speed of the vehicle, and a control unit for controlling operation of the pump, the method comprising the steps of:

• detecting an inner pressure of the accumulator;
• detecting a vehicle speed;
• defining and storing an upper limit pressure value and a lower limit pressure value in the control unit based on the detected vehicle speed;
• comparing the detected inner pressure of the accumulator with the upper and lower limit pressure values;
• activating the pump when the detected inner pressure has reached the lower limit pressure value;
• deactivating the pump when the detected inner pressure has reached the upper limit pressure value;
• and
• adjusting at least one of the upper and lower limit pressure values as the vehicle speed is increased.

A method for controlling a pressure supply system for on-board equipment of a vehicle wherein the pressure supply system incorporates a pump actuated by power drive means, an output conduit connected to an output end of the pump, an accumulator connected to the conduit, a pressure sensor for detecting an inner pressure of the accumulator, a speed sensor for detecting a travelling speed of the vehicle, and a control unit for controlling operation of the pump, the method comprising the steps of:

• detecting an inner pressure of the accumulator;
• detecting a vehicle speed;
• defining and storing a reference pressure value for a predetermined minimum pressure in the control unit;
• comparing the detected inner pressure of the accumulator with the reference pressure value;
• activating the pump when the detected inner pressure has dropped below the reference pressure value;
• deactivating the pump after elapsing of a predetermined time period following such an activation of the pump;
• and
• maintaining the inner pressure of the accumulator above the predetermined minimum pressure based on an output of the pressure sensor.